An alternate title might be 'Plot Holes'. Sometimes it occurs to me to wonder about something, or some motivation in the Pocalypse, then I think about it, and the answer is easily justifiable. Here is a thread to post questions you had to wonder about, or perhaps would like an answer too.

Example.

Question: Why is the base so hard to reach from New Hammerston? The colony is pretty well established, and the base is both very well established and very well equipped, so why is the only way to get there through zombie infested streets? Why is it not connected to New Hammerston with a subway tunnel? Or just a regular tunnel? If the base can sustain a sophisticated AI, surely a small passage isn't that crazy? It would clearly have some use, as the infestation that Joe had to clear for them prevented them from getting to New Hammerston, but if they had a tunnel, they wouldn't have had to worry about that.

Answer: Several probable reasons, all culminating in a tunnel being more hassle then it's worth. 1) the base was built long before the city, so it's unlikely they would have even thought of a tunnel, even if there was somewhere to go. 2) Tunnels are big tasks requiring specialized knowledge, Bernie and Jess's father built the base, not them. Perhaps no-one holds a structural engineering degree. 3) They also require very large and specialized digging equipment, there's no reason for them to have that. 4) Time may be a factor. Everyone is clearly very busy, surviving is hard, and tunnels take a lot of time and resources. 5) The ground may be unsuitable for digging, and with all the abandoned houses, one wrong move could have them coming down. Heck, maybe there are too many sewers and abandoned tunnels already. 6) Jess and Bernie may have never considered a need for it. Sure they got separated from New Hammerston once, but that was probably the first time, and they may consider it a fluke. 7) A tunnel would provide a second access to the base, giving more people the ability to enter the base. Not necessarily cool. 8) If one side of the tunnel gets overrun, the other may be forfeit. (Maybe). 9) Dark underground tunnels. Not cool in a pocalypse situation. May attract rats, bats and bigger vermin, like Vampires, and Mutants.

And finally 10) They do, but we haven't seen it yet, as it may (Or may not) be a secret escape tunnel. Key words, secret (for not your average Joe) and escape (not to be used for ANY OTHER PURPOSE in case it jeopardises the ability to escape through the tunnel.